Carpenter, who has not pitched since Opening Night, will have the medial collateral ligament in his throwing elbow replaced -- commonly known as Tommy John surgery. George Paletta, the club's head orthopedist, will perform the operation.
After several days of consultations with leading doctors including James Andrews, Lewis Yocum and David Altchek, it was determined that Carpenter should have the reconstruction. The typical return time for Tommy John surgery is between 10 and 12 months for starting pitchers, meaning that at least part of the 2008 season is in jeopardy for the '05 Cy Young winner.
"You just want to make sure before you do something like this that you look at every possibility of whether he can be able to pitch without having surgery, because of the long rehab," general manager Walt Jocketty said on Thursday night. "And obviously there was nothing [else] that could be done. I think we wanted to make sure that we got the info from all the other doctors."
Carpenter underwent a procedure in May to remove bone spurs that had become problematic in his elbow. His recovery had been going well until his second Minor League rehabilitation start, and the club had hoped he would return before the end of July. However, after the second start, Carpenter reported swelling and stiffness in the joint.
He shut down throwing at that point and began seeking advice, a process that eventually led to the decision to have surgery. While the club acknowledges that the on-field loss is a major blow, teammates felt for their friend as much as for their playoff chances.
"It's just unfortunate," said Braden Looper. "You just want to tell him that you're thinking about him and to get healthy. Just get whatever it is that's got to be done taken care of, and get back to where you're right. Get 100 percent and be good for years to come. You feel bad for the guy. The guy worked his tail off in rehab to get back to where he could pitch, and then that happens."
Head athletic trainer Barry Weinberg referred questions about the specifics of the operation to Paletta, who was not available for comment on Thursday night. He said that the injury did not result from a single-pitch, traumatic event, but declined to specify whether Carpenter has a complete rupture of the ligament.
Carpenter has undergone two previous elbow surgeries, as well as a pair of shoulder operations. He's never had ligament replacement, however.
"We are so much more concerned for him than we are for us," said manager Tony La Russa. "Chris is a stallion. He's a prince. Being at the top of that rotation, taking the responsibility, competing, when you have talent like that. ... He eats his heart out when he misses a little bit. And to have to go through a rehab, we really are more concerned that he get through it and he handle it."
St. Louis was already seeking to bolster its starting rotation, which ranks 15th in the National League with a 5.23 collective ERA. Jocketty said that Carpenter's loss amplifies that need, but acknowledged that addressing it could be difficult.
"We've been looking to try to improve the rotation, but certainly, there's a more dramatic need now than we had," he said.
The Cardinals are in third place in the National League Central, 9 1/2 games behind the division-leading Brewers. They had been hanging a significant portion of their hopes for a rally on Carpenter's return.
"Everybody's going to have to pick up the slack a little bit and perform," Looper said. "Somebody else is going to have to step up. We're all going to have to as starters continue to try to pitch well. ... It's a group effort. No one person can do it. You can't replace a Cy Young Award winner and the best pitcher in the National League the last few years. You've got to do the best you can and continue to battle."
Jocketty indicated that he does not consider his club any more of a "seller" at the July 31 non-waiver trade deadline, despite the bad news on Carpenter.
"Ultimately we are still continuing to find ways to improve the club," he said. "I think obviously how we play the next week or so will do a lot to determine what we do, what direction we go in. But basically we're still continuing to try to improve. I think we still owe it to our team and to our fans to continue to improve."
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.